Residents in northern China are in for a celestial treat as a stunning aurora borealis is expected to illuminate the night skies in the coming days. According to the China Meteorological Administration’s National Center for Space Weather, solar activity is projected to be at moderate to high levels from Friday, with a chance of M-class or larger solar flares.
Severe geomagnetic storms are anticipated due to coronal mass ejections (CMEs), potentially leading to disturbances in the ionosphere on October 11 and 12. These conditions may create optimal circumstances for observing auroras, particularly from the evening of October 10 to the early morning of October 12. Enthusiasts might witness relatively vivid auroras in northern regions of China, with some areas possibly experiencing rare red and green composite auroras.
Understanding Geomagnetic Storms
Geomagnetic storms occur when CMEs—massive bursts of solar wind and magnetic fields—collide with Earth’s magnetosphere. A single CME event can eject billions of tonnes of solar material traveling at speeds of hundreds of kilometers per second. This influx of energy alters the direction and magnitude of Earth’s geomagnetic field, leading to storm conditions.
Increased Solar Activity and Frequent Storms
Solar activity follows an 11-year cycle of calm and active periods, known as solar cycles. Since entering the 25th solar cycle in December 2019, the sun has exhibited intensified activity, with frequent X-class flares, solar proton events, and strong geomagnetic storms. The current cycle’s frequency and intensity are significantly surpassing those of the previous cycle. Advances in China’s space weather monitoring have enhanced forecasting capabilities, allowing for more accurate predictions of such events.
The Science Behind Auroras
Auroras are mesmerizing light displays resulting from interactions between charged particles from the sun and atoms and molecules in Earth’s upper atmosphere. Guided by Earth’s magnetic field, these particles collide with atmospheric constituents between 100 to 400 kilometers above the surface. The collisions excite the atmospheric particles, which then release energy in the form of light, creating the vibrant colors characteristic of auroras.
Reference(s):
cgtn.com
